Characterization of the U.S. Industrial Commercial Boiler Population

The average boiler size for the industry is 20 MMBtu/hr. The food industry has smaller
and more numerous facilities than the other steam-intensive industries, yielding the large
number of boiler units. The large number of small units is one reason that there is a
higher percentage (58 percent) of natural gas-fired boilers in the food industry than in any
other major industry, since very small boilers tend to burn natural gas. The average
capacity factor of boilers in the food industry is 31 percent, which is less than the 47
percent average of all industries. The seasonal nature of some parts of the food industry
is one reason for the low capacity factor.
2.2.2 Paper Industry
The paper industry has about 3,400 boilers with a total capacity of 376,000 MMBtu/hr.
The industry has more than 200 steam-intensive pulp mills and this is reflected in the
boiler inventory, which has almost 500 boilers larger than 250 MMBtu/hr. The paper
industry includes some of the largest industrial boilers. The large boilers comprise more
than half (230,000 MMBtu/hr) of the industry’s total capacity. The average boiler size
for the industry is 109 MMBtu/hr. Pulp mills consume large quantities of electricity in
addition to steam and the industry utilizes large boiler CHP systems to meet both
requirements. The average capacity factor is 66 percent for the industry’s boilers.
Almost two-thirds of the fuel used in paper industry boilers is “other” or by-product
fuels. The dominant by-product fuel is black liquor, a waste product from the chemical
pulping process. Black liquor has a low heat content (about 6,000 Btu/lb) and boilers
fired with black liquor have an efficiency of about 70 percent, compared to 80 percent-85
percent for coal or natural gas boilers of the same size. In addition to black liquor, the
industry uses bark, wood chips and production wastes. More than 80 percent of paper
industry boiler capacity is located in five regions (East North Central, South Atlantic,
East South Central, West South Central and Pacific) and the greatest concentration is in
the South Atlantic, which includes 26 percent of the capacity.
2.2.3 Chemicals Industry
The chemicals industry has almost 12,000 boilers with a total capacity of 335,000
MMBtu/hr, more than any other industry. Slightly more than half of the boilers (6,700
units) are smaller than 10 MMBtu/hr and 347 are larger than 250 MMBtu/hr. The
average capacity factor of chemical industry boilers is 50 percent. The high number of
large and small boilers is consistent with the nature of the industry, which includes large,
integrated facilities as well as small plants making specialty products such as dyes and
cosmetics. The primary fuels for chemical industry boilers are natural gas (43 percent),
by-products (39 percent) and coal/coke/breeze (15 percent). The chemicals industry has
51 percent of its boiler capacity in the West South Central region with the East North
Central, East South Central and South Atlantic accounting for another 33 percent.
The chemicals industry is one of the most complex and diverse industries in the U.S., and
simple characterizations are impossible. While the EIA Manufacturing Energy
Energy and Environmental Analysis, Inc. 2-3